Saturday, 25 March 2017

Leo Triplet - Finished

The night of the 24th of March was not completely clear but good enough to get the data I needed.

Here's the finished image - have always loved the eerie feeling of this group of galaxies - the one in the upper right is how I remember galaxies being depicted in all the science fiction books I read when I was young. The one on the left is worth zooming in on in the individual shots below. Details of capture parameters follow the pictures at the end of this post.

and each of these galaxies individually



And NGC 3268

Object name
Leo Triplet
Object ID
M65, M66 and NGC 3628
21 and 24 March, 2017
Altair 115mm
8x5 min / 30x2 min / 1.6 hrs
7x5 min / 35 min
6x5 min / 30 min
8x5 min / 40 min
Total time
3.4 hours
PixInsight / fully calibrated lights / Levels / Curves / SCNR only

The skies were not outstanding on either night of imaging this object. I am surprised at how good it turned out considering this.
There is an awful lot of vignetting on the luminance subs which was improved by reducing the exposure time from 300 to 120 seconds.

Alignment of the mount was problematic each night – because I kept aligning on the wrong star! Really must remember that when looking for a 1.4 magnitude star you WILL know it when it appears in on the screen – brighter than anything else besides another <1.4 magnitude star! :-)

Friday, 24 March 2017

The Leo Triplet

Great to be in the observatory again after 2 months of clouds.

I decided to image the Leo Triplet tonight. It's a group of galaxies in Leo that I've managed to image once before with my old one shot colour CCD camera - tonight I'm using the ASI 1600MM and capturing it in LRGB (Luminance, Red, Green and Blue filters).

Here's where it was in my night sky

Image courtesy of Starry Night Pro 7

In this next shot you can see the field of view of my two imaging scopes and why I chose the 115mm tonight.

Image courtesy of Starry Night Pro 7

Things didn't start well. I haven't  used my new camera with the Altair 115mm telescope and quickly found out I couldn't achieve focus - I needed about 2mm more of travel - so close but no good. I could see an element of the camera/field flattener mounting that needed to be eliminated or shortened and decided it was time to shut down and get on line to order the part I need.

This was after I'd got the guide camera calibrated and image framed etc. so about an hour of work seemed lost.

Then, as I was putting the camera away I spotted a spacer that looked suspiciously like the element I needed - it was! It must have come with the camera and I'd forgotten about it.

I could've gone in and given up but as I hadn't "parked" the scope it was still centred on the the target, and although i had disconnected the guide camera I hadn't shut the program down so there was a chance it was still calibrated - it was - and I had everything back up and running in about 15 minutes.

I slewed the scope onto Regulus in Leo to see if I could get focus and noticed that you could easily see the partner in this double star system - pretty cool.

Focus was fine so I started the imaging run after checking the guiding etc.

I was happy to see the first 5 minute subframe come down ok - now it was just a question of clear skies and more data :-)

Unfortunately the luminance frames were very poor so I wasn't able to complete a useful process with the data I captured - but I'll be able to use the RGB data later when I capture more Luminance.